Dash8
. Also a cool trick is to use a cardboard template for the road wheels. You airbrush the black/grey rubber first then put the template hole over the rim and airbrush the rim with base color.
I saw a variation on that I liked. I had been using a draftsman's circle template, trying to cut perfect circles into the masking tape. But it always came out a little ragged no matter how hard I tried.
Then I saw a video of a guy that simply used the template itself as the mask. He put masking tape over the adjacent holes to keep them clean, then simply put each wheel up 'into' the template and sprayed.
When he was done he just wiped the template clean. Genius!
So I went out and found a cheap ($5 plus shipping) template that came in half millimeter increments (ordered two of 'em).
Here. Dew Drafting, Timely 89TM
http://www.draftingsuppliesdew.com/timely-89tm-metric-circles-template